Workers in the art of providing and/or using high speed printers, especially strip printers used for electrographic data processing output, are familiar with the need for simple, light, compact, reliable apparatus, for instance, to be used at remote installations. Workers are being challenged more and more by demands for better reliability, along with reduced size, weight and power requirements and for printing apparatus which is relatively quiet and with fewer moving parts. The present invention is adapted to provide an improved print head and associated fabrication method satisfying such needs, especially as applied to strip printers.
Printers of the type contemplated employ a printing electrode including an arm with a distal marking tip, or stylus, adapted to generate legible print-marks on recording media. Conventional printers requiring inked ribbons and the like are too complex and problematical to operate at the contemplated installations and at speeds required, whereas "electro-sensitive" printers (e.g. spark printers or facsimile electrolytic recorders of the type long employed for recording facsimile images) are commonly considered for such instances. Electrolytic printers employ paper impregnated with an electrolyte, together with a pair of electrodes engaged on opposite sides of the paper, one electrode intended to erode or deplate on the paper surface to thereby create a visible mark thereon. An example of such a technique is described in U.S. Pat. No. 3,713,168 to Baker (commonly assigned) and describing an improved apparatus for making electrolytic media, together with a novel media supply arrangement (relevant portions of this patent being hereby incorporated by reference herein).
In such spark printers and electrolytic printers, one of the electrode elements is commonly skidded over a moving record (paper) surface as the recording electrode stylus, while a ground electrode (typically a grounded metal roller) is engaged on the other side of the record. The subject invention is directed toward an improved print head especially adapted for such printing wherein a foil type electrode-finger is fabricated in a novel manner, being adapted to be resiliently skidded, as the stylus, over the record substrate being selectively energized when recording marks are to be impressed thereby.
For such recording, workers will appreciate that it is all-important to establish and maintain stylus position for accurate, legible printing, especially over extended service life. This is especially so with apparatus like the above-mentioned printers, having a carefully aligned row of such styli electrodes presented across the path of the passing paper strip to selectively impress symbols thereon.
Workers in the art will recognize that such electrodes have heretofore been readily displaced or worn-away in use, or misshapen by record erosion, etc. Such erosion leads to variations in stylus size and/or position, with resultant loss in print quality of course. The present invention provides a method and associated stylus arrangement adapted to meet such problems and provide improved printing without the use of expensive materials and difficulties associated with those commonly used.